Protective Fabric And Process Of Manufacturing Same

ABSTRACT

A fabric for use in arc and flame protection, and a process for producing a fire resistant fabric are provided. The fabric is comprised of: more than 15% aramids; less than 50% modacrylic; less than 50% cellulose; and less than 15% nylon. The process comprises shredding recycled fire resistant garments into fibers; creating yarn from the shredded fibers; weaving the yarn into fabric; and knitting the yarn to produce new garments. The fabric may be used to produce fire-resistant garments worn by workers in many industries such as the oil and gas.

The application claims the benefit of the filing date of U.S.Provisional Application No. 62/326,497, filed on Apr. 22, 2016, thedisclosure of which is herein incorporated by reference in its entirety.The subject application is a continuation-in-part (CIP) of U.S.application Ser. No. 16/933,828 filed on Jul. 20, 2020, which is acontinuation of application of U.S. application Ser. No. 15/491,471filed on Apr. 19, 2017 now patented as U.S. Pat. No. 10,760,189, each ofwhich is herein incorporated by reference in its entirety. A portion ofthe disclosure of this patent document contains material which issubject to copyright protection. The copyright owner has no objection tothe facsimile reproduction by anyone of the patent document or thepatent disclosure, as it appears in the Patent and Trademark Officepatent file or records, but otherwise reserves all copyright rightswhatsoever.

FIELD OF THE INVENTION

The present invention relates generally to a protective fabric and aprocess for producing the fabric. More particularly, the presentinvention relates to a protective fire resistant fabric and a processfor producing the fabric from recycled garments.

BACKGROUND OF THE INVENTION

In the protective garment industry, fire resistant garments used in theoil and gas sector, among other industries, are frequently disposed ofin large quantities. For example in Alberta, Canada, it is estimatedthat 1000 tons of fire resistant garments are disposed of each year.Aramids are estimated to comprise 500 tons of these disposed garments.Aramid fibers are a class of heat-resistant and strong synthetic fibersproduced under trade names such as Nomex, Conex, Arawin, etc. The aramidfiber handles similarly to normal textile apparel fibers, and ischaracterized by excellent resistance to heat as it never melts orignites at normal levels of oxygen. The U.S. Federal Trade Commissiondefines aramid fiber as a manufactured fiber in which the fiber-formingsubstance is a long-chain synthetic polyamide in which at least 85% ofthe amide linkages, (—CO—NH—) are attached directly to two aromaticrings. Disposal presents difficulties as the aramids contain benzenerings and should not be incinerated. Currently, disposal in landfills isthe only option.

U.S. Pat. No. 7,065,950 to E.I. du Pont de Nemours and Company, hereinexpressly incorporated by reference, discloses a flame protective yarn,fabric, and garment that contain modacrylic, p-aramid, and m-aramidfibers. The yarn comprises 40 to 70 weight percent (wt %) modacrylicfiber, 5 to 20 wt % p-aramid fiber, and 10 to 40 wt % m-aramid fiber.The modacrylic fiber is an acrylic synthetic fiber made from a polymercomprised primarily of acrylonitrile. The polymer is a copolymercomprising 30 to 70 wt % of an acrylonitrile and 70 to 30 wt % of ahalogen-containing vinyl monomer. The halogen-containing vinyl monomeris at least one monomer selected, for example, from: vinyl chloride,vinylidene chloride, vinyl bromide, and vinylidene bromide. Examples ofcopolymerizable vinyl monomers are: acrylic acid, methacrylic acid,salts or esters of such acids, acrylamide, methylacrylamide, and vinylacetate. Additives can be used with the aramid and it has been foundthat up to as much as 10 wt % of other polymeric material can be blendedwith the aramid or that copolymers can be used having as much as 10 wt %of other diamine substituted for the diamine of the aramid or as much as10 wt % of other diacid chloride substituted for the diacid chloride ofthe aramid. M-aramids are those aramids where the amide linkages are inthe meta-position relative to each other, and p-aramids are thosearamids where the amide linkages are in the para-position relative toeach other. In the practice of this invention the aramids most oftenused are poly(paraphenylene terephthalamide) and poly(metaphenyleneisophthalamide).

U.S. Pat. No. 7,744,999 to E.I. du Pont de Nemours and Company, hereinexpressly incorporated by reference, discloses a flame protective yarn,fabric, and garment that contain modacrylic, p-aramid, and m-aramidfibers. The yarn consists essentially: of from 50-80 wt % meta-aramidfiber having a degree of crystallinity of at least 20%, 10-30 wt %modacrylic fiber, 5-20 wt % para-aramid fiber, and 1-3 wt % antistaticfiber based on the total weight. The fabric has a basis weight in therange of 5.5 to 7 oz per square yard.

U.S. Pat. No. 8,069,643 to E.I. du Pont de Nemours and Company, hereinexpressly incorporated by reference, discloses a flame protective yarn,fabric, and garment comprising aramid fiber and modacrylic fiber whereinthe modacrylic fiber has less than 1.5 wt % antimony. The fabricconsists essentially of: 50-80 wt % meta-aramid fiber having a degree ofcrystalinity of at least 20%, 10-40 wt % modacrylic fiber that isantimony free, 5-20 wt % para-aramid fiber, and 1-3 wt % antistaticfiber based on the total weight. The fabric has a basis weight in therange of 4 to 12 oz per square yard.

U.S. Pat. No. 8,133,584 to E.I. du Pont de Nemours and Company, hereinexpressly incorporated by reference, discloses a flame protective yarn,fabric, and garment comprising aramid fiber and modacrylic fiber,wherein the modacrylic fiber has less than 1.5 wt % antimony. The fabricconsists essentially: of 50-80 wt % meta-aramid fiber having a degree ofcrystalinity of at least 20%, 10-30 wt % flame-retardant rayon fiber,10-20%wt modacrylic fiber, 0-5 wt % para-aramid fiber, and 0-3 wt %antistatic fiber based on the total weight. The fabric has a basisweight in the range of 5.5 to 7 oz per square yard.

U.S. Pat. No. 7,348,059 (a continuation-in-part of U.S. Pat. No.7,065,950) to E.I. du Pont de Nemours and Company, herein expresslyincorporated by reference, discloses a yarn comprising: 40 to 70 wt %modacrylic fiber, and 5 to 20 wt % p-aramid fiber having a degree ofcrystallinity of at least 20 wt %. The fabric has reduced shrinkage dueto the crystalline nature compared to a fabric wherein the m-aramidfiber is amorphous.

Other techniques for protective garments, yarns, and fabrics aredisclosed in U.S. Publication Nos. 2011/0173734 to Mikhail et al.,2012/0146784 to Hines et al., 2014/0041107 to Rose et al., and2014/0196201 to Guangdong Kingtide Development Co., Ltd., all of whichare herein expressly incorporated by reference.

All of these prior references described above do not disclose yarns,fabrics, and garments suitable for flame protection that use recycledcomponents. It is an object of this invention to provide at least anovel and non-obvious method and fabric comprising at least recycledmaterial from used yarns, fabrics, and garments to avoid sending them tolandfills while maintaining properties suitable for use as protectivegarments.

SUMMARY OF THE INVENTION

According to one embodiment of the invention, there is provided a fabricfor use in arc and flame protection comprising: more than 15 wt %aramids; less than 50 wt % modacrylic; less than 50 wt % cellulose; andless than 15 wt % nylon. The aramid fiber may be 70 wt % aramid fiber,and the modacrylic may be 20 wt % modacrylic. The warp may comprise 2/3of the total weight of the fabric and the weft may comprise 1/3 of thetotal weight of the fabric. The warp may comprise 45 wt % aramids, 13 wt% modacrylic, 6.5 wt % nylon, and 0.65 wt % anti-static material. Thewarp aramids may further comprise 49 wt % virgin aramid fiber and 20 wt% recycled aramid fiber. The weft may comprise 26 wt % aramids, 7 wt %modacrylic, 2 wt % nylon, and 1.4 wt % anti-static material. The weftaramids may further comprise 55 wt % recycled aramid fiber and 18 wt %virgin aramid fiber. The fabric weight in some aspects may be between 6to 7 oz twill.

According to another aspect of the invention, there is provided a warpfor use in a fire resistant fabric comprising 15 to 69 wt %meta-aramids, 19 wt % modacrylic, 10 wt % nylon, and 2 wt % antistaticwith other fabrics.

According to yet another aspect of the invention, there is provided aweft for use in a fire resistant fabric comprising 73 wt % meta-aramids,20 wt % modacrylic, 5 wt % nylon, and 2 wt % anti-static.

According to yet another aspect of the invention, there is provided aprocess for producing a fire resistant fabric, comprising: shreddingrecycled fire resistant garments into fibers, creating yarn from theshredded fibers, weaving the yarn into fabric, and knitting the yarn toproduce new garments. The process may further comprise dry cleaning therecycled garments using a chemical solvent prior to the shredding. Thechemical solvent may be tetrachloroethylene. The process may furthercomprise removing non-fire resistant components from the recycledgarments, prior to the shredding. The shredding may be done by anindustrial fabric shredder. Creating the yarn may comprise carding theshredded fabric to produce a sliver. Creating the yarn may furthercomprise then feeding the sliver through a roving machine. The slivermay be twisted and elongated by the roving machine. The carding may bedone by hundreds of wires in a carding machine. The weaving may be doneusing a loom.

BRIEF DESCRIPTION OF THE DRAWINGS

In the figures which illustrate by way of example only, embodiments ofthe present invention,

FIG. 1 depicts a process for producing fabric from recycled components;

FIG. 2 shows test results for a 3-second exposure to flame test on bluestandard coveralls made from about 70% aramid, 20% modacrylic, 8% nylon,and 2% anti-static, tested with 100% cotton t-shirt and briefs;

FIG. 3 shows test results for a 5-second exposure to flame test on bluecoveralls with visibility trim, double layer elbows and knees, made fromabout 70% aramid, 20% modacrylic, 8% nylon, and 2% anti-static, testedwith 100% cotton t-shirt and briefs;

FIG. 4A shows detailed parameters and results of the 3-second testhaving burn number 4309 from FIG. 2 ;

FIG. 4B is a graph depicting the percentage burn versus time for burnnumber 4309;

FIG. 5A shows detailed parameters and results of the 3-second testhaving burn number 4312 from FIG. 2 ;

FIG. 5B is a graph depicting the percentage burn versus time for burnnumber 4312;

FIG. 6A shows detailed parameters and results of the 3-second testhaving burn number 4314 from FIG. 2 ;

FIG. 6B is a graph depicting the percentage burn versus time for burnnumber 4314;

FIG. 7A shows detailed parameters and results of the 5-second testhaving burn number 4311 from FIG. 3 ;

FIG. 7B is a graph depicting the percentage burn versus time for burnnumber 4311;

FIG. 8A shows detailed parameters and results of the 5-second testhaving burn number 4313 from FIG. 3 ;

FIG. 8B is a graph depicting the percentage burn versus time for burnnumber 4313;

FIG. 9A shows detailed parameters and results of the 5-second testhaving burn number 4315 from FIG. 3 ; and

FIG. 9B is a graph depicting the percentage burn versus time for burnnumber 4315.

DETAILED DESCRIPTION OF THE EMBODIMENT

A process 100 for producing a fire resistant fabric is shown at a highlevel in FIG. 1 . The process begins with the collection and shredding110 of used garments such as coveralls. The garments may initially havecontaminants such as oil, dirt, etc. present thereon. These contaminantsmay be removed through dry cleaning using a chemical solvent such astetrachloroethylene (perchloroethylene) commonly known as “PERC”. Thegarments may then be processed by manually removing any non-fireresistant components such as zippers, snaps, hook and loop fasteners(e.g. Velcro®), etc. After removal of these non-fire resistantcomponents, the garments are shredded by means of an industrial fabricshredder to produce recycled fibers.

At step 120, the recycled fibers are used to make yarn through cardingby hundreds of fine wires in a carding machine, as is known in the art.The carding machine separates the fibers and produces a rope like strandof parallel fibers called a sliver. The sliver is fed through at leastone roving machine, as is known in the art, where it is elongated andgiven additional twists to produce yarn.

At step 130, the yarn is woven into a fabric using a loom as is known inthe art.

The fabric is then knitted at step 140, and then dyed and converted backinto garments at step 150.

In an embodiment, the resulting fabric is 6 to 7 oz twill comprising: upto 70 wt % aramids; about 20 wt % modacrylic; 8 wt % nylon; and 2 wt %anti-static material. The warp comprises approximately 2/3 of the totalweight of the fabric whereas the weft comprises approximately 1/3 of thetotal weight of the fabric.

In another embodiment, the resulting fabric comprises: more than 15 wt %aramids; less than 50 wt % modacrylic; less than 50 wt % cellulose; andless than 15 wt % nylon.

The warp is 45 wt % aramids, 13 wt % modacrylic, 6.5 wt % nylon, and0.65 wt % anti-static material based on total fabric weight. For thewarp aramids, 49 wt % are virgin aramid and 20%wt are recycled aramidsbased on the total fabric weight. Based on only the weight of the warp,the warp comprises 69 wt % meta-aramids, 19 wt % modacrylic, 10 wt %nylon, and 2 wt % anti-static.

The weft is 26 wt % aramids, 7 wt % modacrylic, 2 wt % nylon, and 1.4 wt% anti-static material based on total fabric weight. For the weftaramids, 55 wt % are recycled aramids and 18 wt % are virgin aramidsbased on total fabric weight. Based only on the weight of the weft, theweft comprises 73 wt % meta-aramids, 20 wt % modacrylic, 5 wt % nylon,and 2 wt % anti-static.

The Applicant has found that the resulting fabric produces unexpectedand superior performance in mannequin burn tests. The garments weretested in accordance with ASTM F1930-15 Standard Test Method forEvaluation of Flame Resistant Clothing for Protection Against FireSimulations Using an Instrumented Manikin. The test results wereconducted by the Protective Clothing and Equipment Research Facility(PCERF) at the University of Alberta (reference number P23-009-13).Appendix A, herein incorporated by reference in its entirety. Twogarment systems were evaluated by the tests:

-   1. Blue standard coveralls, GR 2015-TW-1, 70% aramid/20%    modacrylic/8% nylon/2% anti-static, tested with 100% cotton t-shirt    and briefs; and-   2. Blue coveralls with visibility trim, double layer elbows and    knees, GR 2015-TW-1, 70% aramid/20% modacrylic/8% nylon/2%    anti-static, tested with 100% cotton t-shirt and briefs.

The test apparatus used comprised a thermally instrumented mannequin.Flash fires were produced with propane diffusion flames. One hundred andten stimulant sensors were used to measure the rate of heat transfer tothe mannequin. A computer controlled data acquisition system was used torun the test, record and store the data, calculate the extent and natureof the skin damage, and display the results. The sampling rate of thesystem was 1100 Hz.

The tests were conducted on Sep. 24, 2015. The exposure heat flux at thestart of the test was 82.4 kW/m², and at the end was 80.7 kW/m². Thetest room temperature ranged from 15° C. to 22° C., and the relativehumidity ranged between 40% and 50%. Sensor temperature measurements(data collection) were taken for 60 seconds during and after flameexposure. The specimen garments were laundered one time as per AATCC(Association of Textile, Apparel and Materials Professionals) method 13591, V A iii), as described in ASTM F1930-15 paragraph 9.1.4, andconditioned at 21° C. and 65% relative humidity for a minimum of 24hours after laundering. Garments were tested within 10 minutes ofremoval from the conditioned environment.

Tests performed on the first garment system (GR 2015-TW-1 StandardCoveralls) for a 3-second exposure resulted in 14.5% of the mannequinsurface receiving 2^(nd) and 3^(rd) degree burns, and 7.3% of themannequin surface under the garment receiving 2^(nd) degree burns .These results were calculated as the mean of the burn predictions overthree replications of the test. The three replications of the 3-secondtest are summarized in FIG. 2 . More details of the test replicationsare provided in FIGS. 4A, 4B, 5A, 5B, 6A, and 6B. With reference to FIG.2 , it is clear that the garment protected the mannequin surface suchthat there were no (0%) 3^(rd) degree burns, and only approximately 7.3%of the surface received 2^(nd) degree burns. FIGS. 4A, 5A, and 6A showsummarized test parameters and results for the three replications of the3-second test. FIGS. 4B, 5B, and 6B are graphs depicting the percentageof total mannequin surface reaching criteria for 3^(rd) degree burn (insquare dots) as well as the percentage of total mannequin surfacereaching criteria for 2^(nd) and 3^(rd) degree burn (in circular dots),versus time.

Tests performed on the second garment system (GR 2015-TW-1 Coverallswith visibility trim) for a 5-second exposure resulted in 25.6% of themannequin surface receiving 2^(nd) and 3^(rd) degree burns, and 21.8% ofthe mannequin surface under the garment receiving 2^(nd) degree burns.These results were calculated as the mean of the burn predictions overthree replications of the test. The three replications of the 3-secondtest are summarized in FIG. 3 . More details of the test replicationsare provided in FIGS. 7A, 7B, 8A, 8B, 9A, and 9B. With reference to FIG.3 , it is clear that the garment protected the mannequin surface suchthat there were no (0%) 3^(rd) degree burns, and only approximately21.8% of the surface received 2^(nd) degree burns. FIGS. 7A, 8A, and 9Ashow summarized test parameters and results for the three replicationsof the 5-second test. FIGS. 7B, 8B, and 9B are graphs depicting thepercentage of total mannequin surface reaching criteria for 3^(rd)degree burn (in square dots) as well as the percentage of totalmannequin surface reaching criteria for 2^(nd) and 3^(rd) degree burn(in circular dots), versus time.

Although the embodiments described herein demonstrate fabric of between6 to 7 oz twill, other embodiments may be a fabric of between 5.25 to 8oz twill.

Although the embodiments described herein demonstrate a particularprocess for making yarn and fabric, other processes may be used as isknown in the art to produce fabric with similar characteristics asdescribed herein.

The above-described embodiments are intended to be examples of thepresent invention and alterations and modifications may be effectedthereto, by those of skill in the art, without departing from the scopeof the invention, which is defined solely by the claims appended hereto.

What is claimed is:
 1. A fabric for use in arc and flame protectioncomprising: more than 15 wt % aramids; less than 50 wt % modacrylic;less than 50 wt % cellulose; and less than 15 wt % nylon, wherein thearamid fiber comprises recycled aramid fiber obtained from recycled fireresistant garments and virgin aramid fiber, and wherein a mannequinprotected using said fabric experiences no third degree burns after a 3to 5 second exposure to a heat flux of 82.4 kW/m².
 2. The fabricaccording to claim 1, wherein warp of the fabric comprises ⅔ of thetotal weight of the fabric, and wherein weft of the fabric comprises %of the total weight of the fabric.
 3. The fabric according to claim 1,wherein warp of the fabric comprises 45 wt % aramids, 13 wt %modacrylic, 6.5 wt % nylon, and 0.65 wt % anti-static material.
 4. Thefabric according to claim 3, wherein the warp aramids comprise 49 wt %virgin aramid fiber and 20 wt % recycled aramid fiber.
 5. The fabricaccording to claim 1, wherein weft of the fabric comprises 26 wt %aramids, 7 wt % modacrylic, 2 wt % nylon, and 1.4 wt % anti-staticmaterial.
 6. The fabric according to claim 5, wherein the weft aramidscomprises 55 wt % recycled aramid fiber and 18 wt % virgin aramid fiber.7. The fabric according to claim 1, wherein the fabric weight is between6 to 7 oz per square yard.